Current collector



g- 8, 1939- I E. A. LAPHAM 7 2,169,154

cunnsm ,OOLLECTOR Filed Dec. 16, 1958 '2 Sheets-Sheet 1 Aug. 8, 1939.LAPHAM I 2,169,154

CURRENT COLLECTOR Filed Dec. 16, 19258 2 Sheets-Sheet 2 Patented Aug. 8,1939 UNITED STATES PATENT. OFFICE.

CURRENT COLLECTOR Edward A. Lapham, Long Island City, N. Y.

Application December 16, 1938, Serial No. 246,215

6 Claims. (01. 19159.1)

The present invention is directed to new and in gs, and moreparticularly pointed out in the useful improvements in trolley shoeinserts used appended claims.

in the collection of electrical current from a Referring to the drawingsin which numerals of trolley wire. like character designate similarparts throughout In the past, various types of carbonaceous intheseveral views. 5 serts have been employed in connection with trol Fig. 1is a View in side elevation of one form ley shoes. Some of these havebeen composed of of trolley shoe provided with an insert made in plaincarbon while others consisted of composiaccordance with my i ve o tionsof carbon, graphite, and combinations of Fig. 2 is an end view of thesame. these materials along with other powdered sub- Fig. 3 is a topplan view of the trolley shoe l0 stances including metal. It will benoted, howillustrated in Figs. 1 and 2. ever, that when carbon andgraphite materials Fig. 4 is a sectional detail of the insert per se.such as these are pressed as a dry substance or in 5 is a d iew Sim a t2 but illusa plastic state, they must be heat treated at very Br ing amodified form of shoe and insert; ll high temperatures in order to setthe bind rs, Fig. 6 is a transverse sectional detail of the In this heattreatment, certain of the binders insert Shown in F g- 5- and othervolatile materials are driven off, leaviS a View Similar t illustratinga ing a porous structure throughout the insert modified form of trolleyShoe equ pp d wit an which permits moistur to penetrate int th ininsertmade in accordance with my invention.

. sert, Fig. 8 is a transverse section taken on line 8-8 Although thesecarbon inserts may be satisfacof Fig. 7. tory in dry weather, seriousdifficulties have been 9 s a V from'the underside of encountered duringwet and rainy seasons, d Fig. 10 is a view in side elevation of theinsert especially in the wintertime. embodied in Fig. 7, and By a seriesof experiments and tests, I have 11 is a d View Of t e Samefound thatthe pores of a plain carbon or com- In Figs- 1 t0 4, the numeral irepresents e bined carbon-graphite insert absorb moisture main bodyportion of a t y s u ua y c mwhich, with the passage of current throughthe posed of s. hav wa dly xt nding and shoe, causes an electrolysiswhich rapidly disinoppositely p d fl es 2 a ong its upper ed 0 tegratesthe carbon and shortens its life. Fur- The interior of the y s providedwith a subthermore, my experiments showed that in winter Stantiallyrectangular recess d p d o receive months, the accumulated moisture inthe insert my imDIOVed metal impregnated Carbon sert 3, freezes andactually causes a fracture of the the latter being held in p a y aemovable side insert, plate 4 secured to the body by nuts and bolts 5.

It is therefore the primary object of my ininsert 3 in this Particular pio o 35' vention to overcome the disadvantages above myillvelltiehisComposed Wholly o a bonace us noted and to this end I have provided aninsert material impregnated throughout with molten for trolley shoeswhich is impervious to all liqmetal and its upper f ce is p erablytransuids and as a result I have prevented rapid versely concave asshown in Fig. 2 to receive the o integration of the inserts during wetand rainy trolley wlre- In the a u c ure of this type of weather andgreatly increased the useful life of Insert the carbonaceous ember t theinsert form of pure carbon or a combination of graphite According to myinvention, carbon, graphite, with other powfiered silbstances is Pressedor compositions of either of these materials along iggfggfiggggggggfigi;22:; i 3:5252; molten metal so as to completely fill the porous 3 .5323;gy g gi igg gg g gg of insert with m thus render metal introducedunder a pressure sufllcient to mg the Insert lmpPrvmus to lfqmds and atthe thoroughly fill the pores and form a strengthensame t1me,increas1ngthe tensile strength. m network throughout the insert which not With theabove and Other Obj c in View which only increases its tensile strengthmany times will appear as the description 'proceeds, my inand increasesthe wearing qualities of the matevention resides in the novel featureshereinafter rial, but renders the entire insert impervious to set forth,illustrated in the accompanying drawall liquids and moisture.Furthermore, depending upon the type of metal used as the impregnant,the co-eiliclent of friction of the insert may be lowered or increasedas desired to meet the exigencies of the selected use to which thetrolley shoe is to be put.

Thus, on systems where the travel is extremely heavy, it is important tomaintain as low a coefficient of friction as possible in order tominimlze wear on the trolley and increase the life of the shoe, and inthis event, a low friction babbitt material'may be employed as theimpregnant for the inserts. In other localities where there areconsiderable fumes or gases in the air and the travel is light, troublehas developed due to oxidation of the trolley wire, and when ordinarycarbon or graphite inserts are used, the oxidation causes rapid wear andexcessive sparking. By impregnating the carbon insert with a. slightlyabrasive metal, it is possible to clean the trolley wire at the sametime current collection is being effected. In either even, the method ofimpregnation and the general proceuure followed in forming the insertsis the same.

A modified form of trolley shoe of this same general nature is shown inFig. 5 wherein the side plate is eliminated and the trolley shoe iscomposed of two longitudinally split sections la and lb clamped togetherwith the insert 3 secured in place by means of bolts 5. In thisinstance, I may provide a longitudinally extending groove 3a in theupper face of the insert instead of employing a concave surface acrossthe entire upper face of the insert.

It will be noted that the metal impregnated into the carbon body reducesthe contact drop between the insert and the shoe, thus reducingelectrical loses.

Instead of the replaceable type of insert illustrated in Figs. 1 to 6heretofore described, the inserts may be molded into a solid shoe asillustrated in Figs. 7 to 9. In this case, it is possible to cast themetal impregnated insert directly into the shoe, the metal content ofthe insert being such that the molten metal used for the shoe willintermingle with it, thus making a perfect bond between shoe and insert.It will be noted that in the case of an ordinary carbon or graphiteinsert, the difference in the co-eflicient of expansion between theinsert and the metal used for the shoe is such that it is extremelydiflicult to effect a solid bond in attempting to cast an insertdirectly into a shoe.

Referring to Figs. 7 to 9, the metal impregnated insert 3' will be seenencased within the cast metallic shoe body I with its upper concave faceexposed between the flanges 2' for contacting the trolley wire.

In connection with this form of my invention, it will be noted that myimproved insert may be cast, soldered, brazed, or otherwise permanentlysecured within the metallic shoe l' without the use of any additionalclamping means such as in the other forms described.

While I have shown and described several embodiments of my improvedmetal impregnated carbon shoe insert, it will be understood that I donot intend to confine myself in any way to the illustrated uses. Theessence of my invention lies broadly in the use of a metal impregnatedcarbon current collector for use in connection with trolley wires or thelike and wherein the porous structure of the carbon collector is sealedand rendered impervious to moisture.

It will be apparent that a current collector made in accordance with myinvention, regardless of the particular type of adaptation, will receiveand maintain a very high polish from continued use and will possess anincreased tensile strength in addition to being impervious to moistureand liquid. In other words, it possesses all of the advantages ofcollectors heretofore known, and overcomes the objectionable featureswhich have always been present in such collectors.

From the foregoing it is believed that the construction and advantagesof my invention may be readily understood by those skilled in the artwithout further description, it being borne in mind that numerouschanges may be made in the details disclosed without departing from thespirit of my invention as set out in the following claims.

What I claim and desire to secure by Letters Patent is:

1. An electric current collector for trolley wires consisting of a bodyportion composed of compressed carbonaceeous material impregnated withmolten metal, whereby the normally porous structure of said body isrendered impervious to fluids.

2. A current collecting insert for trolley shoes consisting of a bodyportion composed of compressed carbonaceous material impregnated withmolten metal, whereby the normally porous structure of said body isrendered impervious to fluids.

3. In a trolley shoe, a current collecting insert composed of compressedcarbonaceous material impregnated with molten metal, whereby thenormally porous structure of said insert is rendered impervious tofluids.

4. In a trolley shoe, a replaceable current collecting insert composedof compressed carbonaceous material impregnated with motlen metal,whereby the normally porous structure of said insert is renderedimpervious to fluids.

5. A trolley shoe including a metal body portion, a current collectinginsert embedded in said body, said insert being composed of compressedcarbonaceous material impregnated with molten metal, whereby thenormally porous structure of said insert is rendered impervious tofluids.

6. A trolley shoe including a cast metal body portion having embeddedtherein a current collecting insert, said insert being composed ofcompressed carbonaceous material impregnated with molten metal, wherebythe normally porous structure of said insert is rendered impervious tofluids, the metal content of said insert being such that the moltenmetal used in casting the shoe intermingles therewith to form a perfectbond between shoe and insert.

EDWARD A. LAPHAM.

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